So as to meet the demand in recent years for highly functional, small electronics, a laminate type mounting structure has been proposed. In this structure, semiconductor elements (particularly naked IC chips cut out from a wafer) are mounted on film carriers and the film carriers are laminated on a substrate and connected (Japanese Patent Unexamined Publication No. 290048/1990).
For example, conventional laminate type mounting structures have the following construction. That is, as shown in FIG. 13, one semiconductor element 61 is mounted on one TAB tape and plural TAB tapes are laminated on an external circuit board 63. Leads 62 formed on the TAB tapes on respective layers are connected to electrodes 64 of each external circuit board 63.
In manufacturing such laminate type mounting structures, nevertheless, chips on TAB tapes are separately handled until they are laminated, since one chip is mounted on one TAB tape, which is inconvenient in transport and storage.
In the above-mentioned structure, moreover, leads 62 require modification of their bent shape and size thereof in every layer of laminate to reach external circuit board 63, and such modification of the leads requires high technical skills.
When laminating, moreover, positioning of leads 62 of semiconductor element 61 and 64 of the electrodes external circuit board is difficult
It is also problematic that the connections between leads 62 and electrodes 64 of the external circuit board can only be made using a special connection tool (jig).
The TAB tape necessary for the mounting is expensive and the production cost of the above-mentioned structure becomes high. In addition, the above laminate type mounting structure does not have a structure to externally and efficiently release the heat generated in the semiconductor element in each layer.
It is therefore an object of the present invention to solve the above-mentioned problems and to provide a film carrier to be used for fabricating a new laminate type mounting structure.
Another object of the present invention is to provide a new laminate type mounting structure by mounting semiconductor elements on the film carrier of the present invention.
A further object of the present invention is to impart a heat-releasing structure to the laminate type mounting structure of the present invention.